In view of the proliferation of wireless communication usage, numerous proposals have been presented regarding the improvement of service facilities for existing wireless communication systems as well as for next-generation wireless communication systems. Many of the proposed improvements call for the enhanced capabilities and increased implementation of multiple-input, multiple-output (MIMO) and massive-MIMO (M-MIMO) receiver architectures.
To this end, orbital angular momentum (OAM)-based radio-frequency (RF) signals offer an additional spatial dimension, namely, an additional degree of freedom, which can be exploited to enhance the capacity of wireless communication links.
However, conventional implementations of OAM-based RF communications have demonstrated certain deficiencies regarding the effective recovery of OAM signals at far-field distances.